package xyz.yiui.dao;

import java.io.IOException;
import java.io.InputStream;
import java.sql.*;
import java.util.Properties;

///操作数据库的公共类
public class BaseDao {
    private static String driver;
    private static String url;
    private static String username;
    private static String password;

    ///静态代码块，类加载的时候就初始化了
    static{
        Properties properties=new Properties();
        ///通过类加载器读取对应的资源
        InputStream is=BaseDao.class.getClassLoader().getResourceAsStream("database.properties");
        try {
            properties.load(is);
        } catch (IOException e) {
            e.printStackTrace();
        }

        driver=properties.getProperty("driver");
        url=properties.getProperty("url");
        username=properties.getProperty("username");
        password=properties.getProperty("password");

    }

    //获取数据库的连接
    public static Connection getConnection() throws ClassNotFoundException, SQLException {
        Connection connection=null;
        Class.forName(driver);
        connection= DriverManager.getConnection(url,username,password);
        return connection;
    }

    ///编写查询公共方法 为了方便统一关闭，传入参数resultSet等
    public static ResultSet execute(Connection connection, ResultSet resultSet, PreparedStatement preparedStatement ,String sql, Object[] params) throws SQLException {
        preparedStatement=connection.prepareStatement(sql);
        for(int i=0;i<params.length;i++){
            preparedStatement.setObject(i+1,params[i]);
        }
        resultSet=preparedStatement.executeQuery();
        return resultSet;
    }
    ///编写增删改公共方法
    public static int execute(Connection connection, PreparedStatement preparedStatement, String sql, Object[] params) throws SQLException {
        preparedStatement=connection.prepareStatement(sql);
        for(int i=0;i<params.length;i++){
            preparedStatement.setObject(i+1,params[i]);
        }
        int ans=preparedStatement.executeUpdate();
        return ans;
    }

    ///释放资源
    public static boolean closeResource(Connection connection,PreparedStatement preparedStatement,ResultSet resultSet)  {
        boolean flag=true;
        if(resultSet!=null){
            try{
                resultSet.close();
                resultSet=null;///GC回收
            }catch (SQLException e) {
                e.printStackTrace();
                flag = false;
            }
        }
        if(preparedStatement!=null){
            try{
                preparedStatement.close();
                preparedStatement=null;///GC回收
            }catch (SQLException e) {
                e.printStackTrace();
                flag = false;
            }
        }
        if(connection!=null){
            try{
                connection.close();
                connection=null;///GC回收
            }catch (SQLException e) {
                e.printStackTrace();
                flag = false;
            }
        }
        return flag;
    }
}
